My fellow teacher called for help—she needed someone who knew about animals. As a science teacher, I filled the bill. "Oh," she added, "bring a net."

Expecting to find some kind of beast as I entered her classroom, I was greeted instead by the sight of excited kids watching a hummingbird fly around. Rather than use the net, I suggested they hang red paper by an open door. The bird would be drawn to it, I explained, and eventually fly out.

Later, the teacher called back. The trick worked. "Now," she said, "we have two hummingbirds flying around the room."